need ph up...flush or adjust next watering.

[kaBLAM]

my plants are watered every three days.

with today's watering the soil and water tested fine. about three hours later i noticed some purple stems setting in some of the plants, tested their soil and found a ph of 5.9.

i was wondering if i should flush and try to adjust the ph now...or if i can wait until the next watering and try to adjust it then?

i'm worried that the plants may not survive a flush. of course i'm also worried that they may not survive acidic soil.

what would you do? flush? or wait the three days and use ph-adjusted water.

also if anyone wants to throw out any home-recipe ph UP adjusters that would be cool.

thanks!